Preserve return URL when confirming logout

src/Forum/Controller/LogOutController.php

@@ -107,7 +107,8 @@ class LogOutController implements ControllerInterface
         if (array_get($request->getQueryParams(), 'token') !== $csrfToken) {
             $view = $this->view->make('flarum.forum::log-out')
                 ->with('csrfToken', $csrfToken)
-                ->with('forumTitle', $this->settings->get('forum_title'));
+                ->with('forumTitle', $this->settings->get('forum_title'))
+                ->with('return', array_get($request->getQueryParams(), 'return'));
 
             return new HtmlResponse($view->render());
         }

views/log-out.blade.php

@@ -7,7 +7,7 @@
   <p>{{ $translator->trans('core.views.log_out.log_out_confirmation', ['{forum}' => $forumTitle]) }}</p>
 
   <p>
-    <a href="{{ $url->toRoute('logout') }}?token={{ $csrfToken }}" class="button">
+    <a href="{{ $url->toRoute('logout') }}?token={{ $csrfToken }}@if ($return)&return={{ urlencode($return) }}@endif" class="button">
       {{ $translator->trans('core.views.log_out.log_out_button') }}
     </a>
   </p>